Vacuum breaker

ABSTRACT

A vacuum breaker is adopted for use on a water discharge end of a flush valve in a water supply piping system. It includes a valve which has a valve seat with a hollow section to house a plug. The plug is movable up and down under water pressure and a spring on the bottom to actuate flushing or stop flushing. The vacuum breaker further includes a coupling duct and a bushing housed in the coupling duct that is made from a flexible material. The coupling duct has a plurality of apertures near the top end. The outer wall of the bushing and the inner wall of the coupling duct form a gap therebetween. During flushing, the wall of the bushing is expanded outwards under water pressure to close the apertures to stop water overflow through the apertures. When the flushing stops, external air can enter through the apertures and the gap between the coupling duct and the bushing to balance the internal and external pressure and eliminate vacuum, and prevent back siphonage from occurring.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a vacuum breaker installed on a water dischargewater end of a flush valve of toilet devices to eliminate vacuum in theflush valve through a plug which may return automatically and a flexibleand deformable bushing and prevent sewage from counter flowing andcontaminating clean water.

2. Description of the Prior Art

Vacuum breaker is installed in a discharge tube of a flush valve toprevent back siphonage from occurring to the toilet or urinal that wouldresult in counter flow to contaminate clean water. Conventional vacuumbreakers such as those disclosed in U.S. Pat. Nos. 3,334,646 and5,564,460 mainly have a flexible bushing with a discharge endtemporarily open under the pressure of flushing water and closed afterthe flushing finishes. Moreover, the bushing wall will be expandedoutwards during flushing to close air outlets of the water dischargetube to prevent water from overflowing through the air outlets. The airoutlets and the flexible bushing function jointly to prevent the backsiphonage in the water supply piping system. The conventional structureset forth above eliminates the vacuum mainly through materialcharacteristics of the bushing which opens and closes automaticallyunder varying water pressure. However, when fatigues or damage occurs tothe material after used for a period of time, response and controlbecome not accurate, and sewage could counter flow through the notclosely sealed bushing and contaminate drinking water.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a vacuumbreaker which has a rigid mechanism to actuate opening and closing offlushing to overcome the disadvantages occurred to the conventionalvacuum breakers that cannot flush normally due to material fatigue.

Another object of the invention is to provide a vacuum breaker toeliminate the vacuum in the piping to prevent back siphonage fromoccurring.

In order to achieve the foregoing objects, the vacuum breaker accordingto the invention is installed on a water discharge end of a flush valve.It includes a valve, a spring, a coupling duct, a bushing and a nut. Thevalve has a valve seat screwed on the water discharge end of the flushvalve, and has a hollow section housing a plug which is movable up anddown. The plug is coupled with a retaining ring on the bottom and sealsthe bottom end of the valve seat when flushing stops. The coupling ductand the bushing are coupled on the water discharge end of the flushvalve below the valve through the nut. The coupling duct has a firstflange on the top end and a plurality of apertures on the wall below thefirst flange. There is a gap between the outer wall of the coupling ductand the inner wall of a distal end of the nut, and between the innerwall of the coupling duct and the outer wall of the bushing. The bushingis made of a flexible material and formed in a barrel with two openends. It can be deformed as desired under water pressure. The spring hasone end pressing the bottom of the plug and other end coupled on a strutin the coupling duct.

By means of the construction set forth above, during flushing, theretaining ring on the lower side of the plug is moved downwards underwater pressure to compress the spring. When the flush valve stopsflushing, the elastic force of the spring pushes the plug upwards andthe retaining ring seals the bottom end of the valve seat to preventsewage in the toilet devices from counter flowing to the clean water.Moreover, during flushing, water passes through the bushing and forms apressure on the wall of the bushing, and presses the flexible wallpartly outwards to contact the inner wall of the coupling duct and sealthe apertures of the coupling duct. Hence water does not over flowthrough the apertures. In addition, when flushing is stopped, waterpressure on the wall of the bushing is absent, and outward deformationof the bushing does not take place, hence the apertures remain open, andexternal air can flow into the vacuum breaker through the apertures andthe gap between the inner wall of the coupling duct and the outer wallof the bushing to balance the internal and external pressure of thevacuum breaker and eliminate the vacuum, and the back siphonage thatmight otherwise occur.

The foregoing, as well as additional objects, features and advantages ofthe invention will be more readily apparent from the following detaileddescription, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of an embodiment of the invention in anon-flushing condition;

FIG. 2 is a top view of an embodiment of the plug of the invention;

FIG. 3 is a schematic view of an embodiment of the invention in aflushing condition;

FIG. 4 is a schematic view of an embodiment of the invention in anoperating condition to eliminate vacuum; and

FIG. 5 is a schematic view of an embodiment of the invention in anoperating condition to prevent counter flow.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Refer to FIGS. 1 and 2 for an embodiment of the vacuum breaker of theinvention. It is installed on a water discharge end 91 of a flush valve9. It includes a valve 1, a spring 2, a coupling duct 3, a bushing 4 anda nut 5. The valve 1 has a valve seat 11 screwing in the water dischargeend 91 of the flush valve 9. The bottom of the valve seat is coupledwith an O-ring 15. The valve seat 11 has a hollow section 12 to house aplug 13 which is movable up and down. The plug 13 has a bottom coupledwith a retaining ring 14 which seals a bottom end 111 of the valve seat11 when flushing is stopped. The plug 13, referring to FIG. 2, has across rib 131 on a upper side forming a plurality of water inlets 132corresponding to the hollow section 12 of the valve seat 11 so thatwater flushing from the flush valve 9 passes through the plug and isdivided into several water streams to become a more stable water flow.The spring 2 has one end pressing the bottom of the plug 13 and otherend coupled on a center strut 32 located in the coupling duct 3. Whenthe retaining ring 14 is moved downwards under pressure of the flushingwater, the spring is compressed. When flushing stops, the springreleases a returning elastic force to push the plug 13 upwards and movethe retaining ring 14 to seal the bottom end of the valve seat 11. Thecoupling duct 3 has a first flange 31 on the top end with a diametergreater than the body thereof. The flange can be coupled on the bottomend of internal screw threads 51 of the nut 5. The nut 5 is screwed withexternal screw threads 92 formed on the water discharge end 91 on alower side of water discharge end 91. The duct wall 33 below the firstflange 31 has a plurality of apertures 331. The duct wall 33 and aninner wall 52 at a distal end of the nut 5 form a gap. The coupling duct3 has a coupling end 34 on a lower side that has external screw threadsto be coupled with a water discharge tube 93. The bushing 4 is made froma flexible material and formed in a barrel with two open ends. It can bedeformed slightly when subject to water pressure. The bushing 4 has asecond flange 41 on the top end which is sandwiched between the bottomof the water discharge end 91 and the first flange 31 of the couplingduct 3 when they are installed by screwing the nut 5. Thus the bushing 4is housed in the coupling duct 3. The outer wall of the bushing 4 andthe inner wall of the coupling duct 3 forms a gap 61 as shown in FIG. 5.

Refer to FIGS. 3, 4 and 5 for the vacuum breaker of the invention isoperating conditions. In the non-flushing condition, the wall of thebushing 4 does not receive water pressure and does not deform outwards,hence the apertures 331 are not sealed. External air can enter throughthe apertures 331 and the gap 61 into the vacuum breaker as shown inFIG. 5. Therefore the internal and external pressures of the vacuumbreaker are balanced, and vacuum does not exist. As a result, backsiphonage can be avoided. When the flush valve 9 is flushed manually orunder automatic control, water (shown by arrows in the drawings) entersthrough the water inlets 132 of the plug 13, and water pressure pushesthe retaining ring 14 and moves the plug 13 downwards and compresses thespring 2. When the water passes through the bushing 4, it pushes thewall 42 of the flexible bushing to expand a portion thereof outwards tobe in contact with the inner wall of the coupling duct 3 to close theapertures 331 of the coupling duct 3. Therefore water does not flow outthrough the apertures 331, as shown in FIG. 4. On the other hand, whenwater discharge decreases gradually, water pressure reduces, thereturning elastic force of the spring 3 increases and pushes the plug 13upwards, and finally the retaining ring 14 seals the bottom end of thevalve seat 11 to stop flushing. And the sewage at the other end of thetoilet devices does not counter flow through the valve 1 to the cleanwater.

While the preferred embodiment of the invention has been set forth forthe purpose of disclosure, modifications of the disclosed embodiment ofthe invention as well as other embodiment thereof may occur to thoseskilled in the art. Accordingly, the appended claims are intended tocover all embodiments which do not depart from the spirit and scope ofthe invention.

1. A vacuum breaker adopted for use in a water discharge end of a flushvalve in a water supply piping system, comprising: a valve having avalve seat screwed on the water discharge end, the valve seat having ahollow section to house a plug which is movable up and down, the plugbeing coupled with a retaining ring on the bottom thereof; a couplingduct located below the valve having a first flange on the top end, aplurality of apertures formed on the wall abutting a lower side of thefirst flange, and a coupling end on a distal end opposing the firstflange; a spring having one end pressing the bottom of the plug andother end coupled on a center strut located in the coupling duct; abushing housed in the coupling duct being made from a flexible materialand formed in a barrel which has two open ends, and having a secondflange on a top end; and a nut having internal screw threads to screwthe coupling duct and the rest elements in the water discharge end ofthe flush valve.
 2. The vacuum breaker of claim 1, wherein the retainingring seals the bottom end of the valve seat when flushing stops.
 3. Thevacuum breaker of claim 1, wherein the plug has a cross rib on a upperside to form a plurality of water inlets corresponding to the hollowsection of the valve seat to divide water flow.
 4. The vacuum breaker ofclaim 1, wherein the bushing has an outer wall in contact with an innerwall of the coupling duct when flushing stops.
 5. The vacuum breaker ofclaim 1, wherein the coupling duct has an outer wall which forms a gapwith an inner wall of a distal end of the nut.